@article{10_4064_sm158_2_3,
     author = {Guillermo P. Curbera and Werner J. Ricker},
     title = {Optimal domains for the kernel operator
 associated with {Sobolev's} inequality},
     journal = {Studia Mathematica},
     pages = {131--152},
     publisher = {mathdoc},
     volume = {158},
     number = {2},
     year = {2003},
     doi = {10.4064/sm158-2-3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm158-2-3/}
}